From 59a7c32126f7aa856221d080fa9eaba3d8bde1d2 Mon Sep 17 00:00:00 2001
From: Patrick Williams <iawillia@us.ibm.com>
Date: Thu, 13 May 2010 23:14:01 -0500
Subject: Boot, set 64bit mode, relocate from ROM.

---
 kernel.c  | 14 ++++++++++++++
 kernel.ld | 40 +++++++++++++++++++++++++++++++++++++++
 makefile  | 17 +++++++++++++++++
 start.S   | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 135 insertions(+)
 create mode 100644 kernel.c
 create mode 100644 kernel.ld
 create mode 100644 makefile
 create mode 100644 start.S

diff --git a/kernel.c b/kernel.c
new file mode 100644
index 000000000..fe019e583
--- /dev/null
+++ b/kernel.c
@@ -0,0 +1,14 @@
+
+void _main(void)
+{
+    unsigned int i = 100;
+    while(i != 0)
+    {
+	asm volatile("eieio");
+	i--;
+    }
+
+    while(1)
+    {
+    }
+}
diff --git a/kernel.ld b/kernel.ld
new file mode 100644
index 000000000..9b7ddd6e0
--- /dev/null
+++ b/kernel.ld
@@ -0,0 +1,40 @@
+base_load_address = 0xfff00000;
+text_load_address = 0xfff08000;
+hreset_load_address = 0xfffffffc;
+
+SECTIONS
+{
+    . = base_load_address;
+
+    .text.intvects ALIGN(0x1000): {
+	*(.text.intvects)
+    }
+
+    . = text_load_address;
+    .text ALIGN(0x1000): {
+	*(.text)
+	*(.rodata)
+	*(.rodata.*)
+    }
+
+    .data ALIGN(0x1000): {
+	*(.data)
+	*(.data.*)
+	*(.branch_lt)
+	*(.opd)
+
+	*(.bss)
+    }
+
+    . = hreset_load_address;
+    .text.hreset : {
+	*(.text.hreset)
+    }
+
+    /DISCARD/ : {
+	*(.comment)
+	*(.gnu.attributes)
+    }
+}
+
+
diff --git a/makefile b/makefile
new file mode 100644
index 000000000..df8bff977
--- /dev/null
+++ b/makefile
@@ -0,0 +1,17 @@
+CC = powerpc64-unknown-linux-gnu-gcc
+LD = powerpc64-unknown-linux-gnu-ld
+
+CFLAGS = -O3
+
+OBJECTS = start.o kernel.o
+
+all: kernel.elf kernel.bin
+
+kernel.elf: ${OBJECTS} kernel.ld
+	${LD} ${LDFLAGS} ${OBJECTS} -T kernel.ld -o kernel.elf
+
+kernel.bin: ${OBJECTS} kernel.ld
+	${LD} ${LDFLAGS} ${OBJECTS} --oformat=binary -T kernel.ld -o kernel.bin
+
+clean:
+	(rm -f ${OBJECTS} kernel.elf kernel.bin)
diff --git a/start.S b/start.S
new file mode 100644
index 000000000..e3d7f6d35
--- /dev/null
+++ b/start.S
@@ -0,0 +1,64 @@
+.section .text.intvects
+
+.global _start
+_start:
+    ;// Enter 64 bit mode
+    mfmsr 0
+    lis 11, 0x8000
+    sldi 11,11, 32
+    or 11,11,0
+    mtmsr 11
+    isync
+    
+    ;// Relocate code
+    bl pre_relocate	;// fill LR with address
+pre_relocate:
+    mflr 2
+    lis 1,0x0010
+    cmp 0,2,1		;// Check LR is less than 1MB
+    bc 0,0,finished_relocate	;// No need to relocate if less than 1MB
+    
+    ;// Get addresses for relocation.
+    ;// Write address in r5
+    ;// Read address in r1
+    li 5,0
+    li 1, -1	;// fill r1 with ffff..ffffff
+    lis 3, 0x1
+    subi 3,3,1	;// fill r3 with 0000..00ffff
+    xor 1,1,3	;// mask off r1  ffff..ff0000
+
+    and 1,1,2	;// and with pre_relocate's address from r2 to get start of
+		;// rom section.
+    
+    ;// Moving 1MB , so load r2 with (1MB / 8 bytes per word)
+    lis 2, 0x2
+    mtctr 2
+relocate_loop:
+    ld 4, 0(1)
+    std 4, 0(5)
+    dcbt 0,1
+    sync
+    icbi 0,5
+    sync
+    addi 1,1,8
+    addi 5,5,8
+    bdnz+ relocate_loop
+    isync
+    
+    ;// Now that we've relocated, erase exception prefix.
+    mfmsr 11
+    li 10, 0x40 ;// bit 6 is MSR_EP
+    not 10,10
+    and 11,11,10
+    mtmsr 11
+
+finished_relocate: 
+    b _main
+
+.org _start + 0x100
+intvect_system_reset:
+    b _start
+
+.section .text.hreset
+hreset:
+    b _start
-- 
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